840 M. Struve and Prof. Amici’s Observations on Double Stars . 
The following observations were made by Professor Amici of 
Modena, by means of a micrometer of bis own construction. 
Distances , 
Names of the Stars. 
Amici. 
Herschel . 
% Bootes, 
6".40"' 
3".23'" 
a Hercules, 
. 4.24 
4 .34 
7T Bootes, 
6.12 
6 .171 
y Virgo, 
3.18 
7 .333 
£ Great Bear. 
13 .16 
14 . 5 
/3 Swan, 
33.8 
39 .32 
In the years 1800 and 1801, M. Triesnecker measured by 
means of a Dollond’s divided object-glass micrometer, the dis- 
tance of the two stars in £ of the Great Bear, and obtained 15."4 
as the mean of 41 observations, which agreed to the fraction of 
a second. Baron Zach has calculated the distance at 16".009? 
from Piazzi’s first Catalogue for 1800; and M. Struve com- 
puted it at 15".91, from Piazzi’s second Catalogue. 
The following Table, abridged from that of Baron Zuch, 
contains a comparison of the observations of Sir William Her- 
schel and M, Struve, on a number of double stars, not given 
in the preceding paper. 
TABLE of the Distances of several Double Stars , according 
to the Observations of Sir William Herschel and M. Struve . 
Names of the Stars. 
c 
■§P 
2 
For 1823. 
Distances. 
R, Ascen. 
in Time, 
Declina- 
tions. 
Struve, 
in 1819. 
Herschel, 
in 1782. 
1 8 « Cassiopeia, 
3 
Oh 
31' 
55° 
34' N 
58", 
o 
CO 
53" 
65 Pisces, 
6 
0 
40 
26 
44 — 
5, 
77 
— 
a Polaris, 
2 
0 
57 
88 
22 — 
18, 
27 
17 
57 y Andromeda, 
2 
1 
53 
41 
29 — 
10, 
48 
9 
Mira, - 
2 
2 
10 
3 
47 — 
114, 
25 
— 
30 Aries, 
7 
2 
27 
23 
52 S 
38, 
26 
31 
» Perseus, 
4 
2 
38 
55 
9 — 
28, 
50 
26 
48 o* Orion, 
4 
5 
30 
2 
43 N 
13, 
60 
11 
13 a Great Bear, 
5 
8 
55 
67 
52 — 
7, 
19 
8 
38 Lynx, 
4 
9 
8 
37 
33 — 
5, 
08 
— 
23 h Great Bear, 
4 
9 
17 
63 
50 — 
21, 
64 
19 
12 Greyhounds, 
3 
12 
48 
39 
17 — 
19, 
87 
20 
21 i Bootes, 
4 
14 
10 
52 
11 — 
38, 
55 
37 
39 Bootes, 
6 
14 
44 
49 
27 S 
5, 
00 
— 
15 £ Balance, 
6 
14 
47 
10 
41 — 
9, 
31 
— 
7 i Northern Crown, 
4 
15 
33 
37 
13 N 
7, 
25 
5 
y Hercules, 
3 
16 
14 
19 
35 — 
40, 
80 
42 
17 Dragon, 
5 
16 
32 
53 
17 — 
4, 
19 
